Is there a way to add some sort of metadata to a map chunk?

[0gb.us]

Is there a way to add some sort of meta data to a map chunk? Alternatively, is there a way to find the map chunk (by some sort of identifier that could be used later, so the data could be stored in a separate file) a block is in when it is placed?

Thanks!

EDIT: I just realized that even if there isn't an official way, I can use addition, subtraction, modulo division, regular division, and rounding to get what I need. An official way would be better if it exists though, as it would be more efficient.